Cloud Queue Tombstone

ABSTRACT

Example techniques relate to cloud queue tombstones. An example implementation may involve a computing system receiving instructions to remove a particular media item from a playback queue. Based on the instructions, the computing system removes the particular media item from the playback queue and adds, to the playback queue, a tombstone indicator indicating that the particular media item has been removed from the playback queue. The computing system receives, from the media playback system, a request for a window of one or more media items from the playback queue. Based on the request, the computing system sends, to the media playback system, data representing a particular window of media items from the playback queue, wherein the particular window includes the tombstone indicator. The computing system detects a given tombstone removal trigger from among multiple tombstone removal triggers and based on the detecting, removes the tombstone indicator from the playback queue.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 120 to, and is acontinuation of, U.S. Non-Provisional patent application Ser. No.15/681,675, filed on Aug. 21, 2017, entitled “Cloud Queue Item Removal,”which is incorporated herein by reference in its entirety.

U.S. Non-Provisional patent application Ser. No. 15/681,675 claimspriority under 35 U.S.C. § 120 to, and is a continuation of, U.S.Non-Provisional patent application Ser. No. 14/485,261, filed on Sep.12, 2014, entitled “Cloud Queue Item Removal,” issued as U.S. Pat. No.9,742,839 on Aug. 22, 2017, which is incorporated herein by reference inits entirety.

FIELD OF THE DISCLOSURE

The disclosure is related to consumer goods and, more particularly, tomethods, systems, products, features, services, and other elementsdirected to media playback or some aspect thereof.

BACKGROUND

Options for accessing and listening to digital audio in an out-loudsetting were limited until in 2003, when SONOS, Inc. filed for one ofits first patent applications, entitled “Method for Synchronizing AudioPlayback between Multiple Networked Devices,” and began offering a mediaplayback system for sale in 2005. The Sonos Wireless HiFi System enablespeople to experience music from many sources via one or more networkedplayback devices. Through a software control application installed on asmartphone, tablet, or computer, one can play what he or she wants inany room that has a networked playback device. Additionally, using thecontroller, for example, different songs can be streamed to each roomwith a playback device, rooms can be grouped together for synchronousplayback, or the same song can be heard in all rooms synchronously.

Given the ever growing interest in digital media, there continues to bea need to develop consumer-accessible technologies to further enhancethe listening experience.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technologymay be better understood with regard to the following description,appended claims, and accompanying drawings where:

FIG. 1 shows an example media playback system configuration in whichcertain embodiments may be practiced;

FIG. 2 shows a functional block diagram of an example playback device;

FIG. 3 shows a functional block diagram of an example control device;

FIG. 4 shows an example controller interface;

FIG. 5 shows an computing system that may practice certain embodiments;

FIG. 6 shows an example cloud computing system in which certainembodiments may be practiced;

FIG. 7 is an example flow diagram for removing a media item from aqueue;

FIG. 8A is an example playback queue;

FIG. 8B is an instance of the example playback queue in which a mediaitem is removed from the queue;

FIG. 8C is an instance of the example playback queue in which anindication that the media item was removed is added to the playbackqueue;

FIG. 8D is an instance on the example playback queue in whichindications that two media items were removed from the queue are addedto the playback queue; and

FIG. 8E is an instance of the example playback queue in which theindications are removed from the playback queue.

The drawings are for the purpose of illustrating example embodiments,but it is understood that the inventions are not limited to thearrangements and instrumentality shown in the drawings.

DETAILED DESCRIPTION I. Overview

Some examples described herein involve, inter alia, removing a mediaitem from a cloud queue. Such examples assist in maintaining consistencybetween a cloud-based audio queue and one or more copies (e.g., arepresentation or other indication) of the cloud-based audio queue thatare maintained by a media playback system (e.g., by one or more playbackdevices of the media playback system).

In some examples, a computing system may maintain or have access to acloud-based playback queue of media items. Such a computing system mayassist in providing a cloud service. One aspect of the cloud service mayinvolve providing a media playback system access to the cloud-basedplayback queue. The media playback system and the computing system mayexchange messages to maintain consistency between the cloud-basedplayback queue and one or more copies of the playback queue that aremaintained by the media playback system. As different techniques forrepresenting playback queues exist, such copies may be copies of theinformation contained in the respective queues (e.g., the media itemsqueued and their ordering) and not necessarily exact duplicates of thequeues themselves. For instance, when the cloud-based playback queue isaltered (e.g., a media item is added, removed, or re-arranged), thecomputing system may notify the media playback system that thecloud-based playback queue has been altered, perhaps by sending amessage to the media playback system via a network interface. Based onreceiving such a message, the media playback system may send a requestfor one or more media items from the cloud-based playback queue so as tosynchronize its copy of the cloud-based playback queue (or a partthereof) with the cloud-based playback queue. The computing system maythen respond with a list of media items from the cloud-based playbackqueue.

From time to time, the computing system may remove a given media itemfrom the cloud-based playback queue, perhaps based on a message receivedfrom another device via a network interface instructing the computingsystem to remove the media item. In such a case, the computing systemmay add to the queue an indication that the given media item has beenremoved from the queue. Such an indication may be sent to the mediaplayback system, perhaps as part of a response to a request for one ormore media items.

Further, the computing system may maintain the indication in thecloud-based playback queue until one or more conditions have beensatisfied. Maintaining the indication may be advantageous in somecircumstances. For example, if the indication is not maintained, and ifthe media playback system does not receive the notification that thecloud-based playback queue has been altered (or if the notification isnot sent), the media playback system might not ever receive notificationof the alteration of the cloud-based playback queue. However, if theindication is maintained, the media playback system may later receivethe indication in a message (e.g., in a subsequent request for mediaitems) and, based on the indication, detect that the media item has beenremoved from the cloud-based playback queue.

Such conditions may involve receiving more than a threshold number ofrequests for one or more media items. For instance, after adding theindication (that the given media item has been removed) to thecloud-based playback queue, the computing system may receive one or morerequests for one or more media items from the cloud-based playbackqueue. After receiving more than the threshold number of requests, thecomputing system may remove the indication from the queue. Maintainingthe indication until the computing system has received more than thethreshold number of requests increases the likelihood that the mediaplayback system has detected that the given media item has been removed.For instance, as the number of requests increases, so too does theprobability that an indication that the media item has been removed hasbeen included in at least one of the lists of media items sent to themedia playback system. Other examples of such conditions exist.

As indicated above, the present application involves removing a mediaitem from a playback queue. In one aspect, a method is provided. Themethod may involve removing a given media item from a queue of mediaitems. The method may further involve adding to the queue an indicationthat the given media item has been removed from the queue. Afterreceiving the one or more requests, the method may also involvedetermining that the computing system has received more than a thresholdnumber of requests for one or more media items since adding to the queuethe indication. After determining that the computing system has receivedmore than the threshold number of requests, the method may furtherinvolve removing the indication from the queue.

In another aspect, a device is provided. The device includes a networkinterface, at least one processor, a data storage, and program logicstored in the data storage and executable by the at least one processorto perform functions. The functions may include removing a given mediaitem from a queue of media items. The functions may further includeadding to the queue an indication that the given media item has beenremoved from the queue. After receiving the one or more requests, thefunctions may also include determining that the computing system hasreceived more than a threshold number of requests for one or more mediaitems since adding to the queue the indication. After determining thatthe computing system has received more than the threshold number ofrequests, the functions may further include removing the indication fromthe queue.

In yet another aspect, a non-transitory computer readable memory isprovided. The non-transitory computer readable memory has stored thereoninstructions executable by a computing device to cause the computingdevice to perform functions. The functions may include removing a givenmedia item from a queue of media items. The functions may furtherinclude adding to the queue an indication that the given media item hasbeen removed from the queue. After receiving the one or more requests,the functions may also include determining that the computing system hasreceived more than a threshold number of requests for one or more mediaitems since adding to the queue the indication. After determining thatthe computing system has received more than the threshold number ofrequests, the functions may further include removing the indication fromthe queue.

It will be understood by one of ordinary skill in the art that thisdisclosure includes numerous other embodiments. It will be understood byone of ordinary skill in the art that this disclosure includes numerousother embodiments. While some examples described herein may refer tofunctions performed by given actors such as “users” and/or otherentities, it should be understood that this description is for purposesof explanation only. The claims should not be interpreted to requireaction by any such example actor unless explicitly required by thelanguage of the claims themselves.

II. Example Operating Environment

FIG. 1 illustrates an example configuration of a media playback system100 in which one or more embodiments disclosed herein may be practicedor implemented. The media playback system 100 as shown is associatedwith an example home environment having several rooms and spaces, suchas for example, a master bedroom, an office, a dining room, and a livingroom. As shown in the example of FIG. 1, the media playback system 100includes playback devices 102-124, control devices 126 and 128, and awired or wireless network router 130.

Further discussions relating to the different components of the examplemedia playback system 100 and how the different components may interactto provide a user with a media experience may be found in the followingsections. While discussions herein may generally refer to the examplemedia playback system 100, technologies described herein are not limitedto applications within, among other things, the home environment asshown in FIG. 1. For instance, the technologies described herein may beuseful in environments where multi-zone audio may be desired, such as,for example, a commercial setting like a restaurant, mall or airport, avehicle like a sports utility vehicle (SUV), bus or car, a ship or boat,an airplane, and so on.

a. Example Playback Devices

FIG. 2 shows a functional block diagram of an example playback device200 that may be configured to be one or more of the playback devices102-124 of the media playback system 100 of FIG. 1. The playback device200 may include a processor 202, software components 204, memory 206,audio processing components 208, audio amplifier(s) 210, speaker(s) 212,and a network interface 214 including wireless interface(s) 216 andwired interface(s) 218. In one case, the playback device 200 may notinclude the speaker(s) 212, but rather a speaker interface forconnecting the playback device 200 to external speakers. In anothercase, the playback device 200 may include neither the speaker(s) 212 northe audio amplifier(s) 210, but rather an audio interface for connectingthe playback device 200 to an external audio amplifier or audio-visualreceiver.

In one example, the processor 202 may be a clock-driven computingcomponent configured to process input data according to instructionsstored in the memory 206. The memory 206 may be a tangiblecomputer-readable medium configured to store instructions executable bythe processor 202. For instance, the memory 206 may be data storage thatcan be loaded with one or more of the software components 204 executableby the processor 202 to achieve certain functions. In one example, thefunctions may involve the playback device 200 retrieving audio data froman audio source or another playback device. In another example, thefunctions may involve the playback device 200 sending audio data toanother device or playback device on a network. In yet another example,the functions may involve pairing of the playback device 200 with one ormore playback devices to create a multi-channel audio environment.

Certain functions may involve the playback device 200 synchronizingplayback of audio content with one or more other playback devices.During synchronous playback, a listener will preferably not be able toperceive time-delay differences between playback of the audio content bythe playback device 200 and the one or more other playback devices. U.S.Pat. No. 8,234,395 entitled, “System and method for synchronizingoperations among a plurality of independently clocked digital dataprocessing devices,” which is hereby incorporated by reference, providesin more detail some examples for audio playback synchronization amongplayback devices.

The memory 206 may further be configured to store data associated withthe playback device 200, such as one or more zones and/or zone groupsthe playback device 200 is a part of, audio sources accessible by theplayback device 200, or a playback queue that the playback device 200(or some other playback device) may be associated with. The data may bestored as one or more state variables that are periodically updated andused to describe the state of the playback device 200. The memory 206may also include the data associated with the state of the other devicesof the media system, and shared from time to time among the devices sothat one or more of the devices have the most recent data associatedwith the system. Other embodiments are also possible.

The audio processing components 208 may include one or moredigital-to-analog converters (DAC), an audio preprocessing component, anaudio enhancement component or a digital signal processor (DSP), and soon. In one embodiment, one or more of the audio processing components208 may be a subcomponent of the processor 202. In one example, audiocontent may be processed and/or intentionally altered by the audioprocessing components 208 to produce audio signals. The produced audiosignals may then be provided to the audio amplifier(s) 210 foramplification and playback through speaker(s) 212. Particularly, theaudio amplifier(s) 210 may include devices configured to amplify audiosignals to a level for driving one or more of the speakers 212. Thespeaker(s) 212 may include an individual transducer (e.g., a “driver”)or a complete speaker system involving an enclosure with one or moredrivers. A particular driver of the speaker(s) 212 may include, forexample, a subwoofer (e.g., for low frequencies), a mid-range driver(e.g., for middle frequencies), and/or a tweeter (e.g., for highfrequencies). In some cases, each transducer in the one or more speakers212 may be driven by an individual corresponding audio amplifier of theaudio amplifier(s) 210. In addition to producing analog signals forplayback by the playback device 200, the audio processing components 208may be configured to process audio content to be sent to one or moreother playback devices for playback.

Audio content to be processed and/or played back by the playback device200 may be received from an external source, such as via an audioline-in input connection (e.g., an auto-detecting 3.5 mm audio line-inconnection) or the network interface 214.

The network interface 214 may be configured to facilitate a data flowbetween the playback device 200 and one or more other devices on a datanetwork. As such, the playback device 200 may be configured to receiveaudio content over the data network from one or more other playbackdevices in communication with the playback device 200, network deviceswithin a local area network, or audio content sources over a wide areanetwork such as the Internet. In one example, the audio content andother signals transmitted and received by the playback device 200 may betransmitted in the form of digital packet data containing an InternetProtocol (IP)-based source address and IP-based destination addresses.In such a case, the network interface 214 may be configured to parse thedigital packet data such that the data destined for the playback device200 is properly received and processed by the playback device 200.

As shown, the network interface 214 may include wireless interface(s)216 and wired interface(s) 218. The wireless interface(s) 216 mayprovide network interface functions for the playback device 200 towirelessly communicate with other devices (e.g., other playbackdevice(s), speaker(s), receiver(s), network device(s), control device(s)within a data network the playback device 200 is associated with) inaccordance with a communication protocol (e.g., any wireless standardincluding IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4Gmobile communication standard, and so on). The wired interface(s) 218may provide network interface functions for the playback device 200 tocommunicate over a wired connection with other devices in accordancewith a communication protocol (e.g., IEEE 802.3). While the networkinterface 214 shown in FIG. 2 includes both wireless interface(s) 216and wired interface(s) 218, the network interface 214 may in someembodiments include only wireless interface(s) or only wiredinterface(s).

In one example, the playback device 200 and one other playback devicemay be paired to play two separate audio components of audio content.For instance, playback device 200 may be configured to play a leftchannel audio component, while the other playback device may beconfigured to play a right channel audio component, thereby producing orenhancing a stereo effect of the audio content. The paired playbackdevices (also referred to as “bonded playback devices”) may further playaudio content in synchrony with other playback devices.

In another example, the playback device 200 may be sonicallyconsolidated with one or more other playback devices to form a single,consolidated playback device. A consolidated playback device may beconfigured to process and reproduce sound differently than anunconsolidated playback device or playback devices that are paired,because a consolidated playback device may have additional speakerdrivers through which audio content may be rendered. For instance, ifthe playback device 200 is a playback device designed to render lowfrequency range audio content (i.e. a subwoofer), the playback device200 may be consolidated with a playback device designed to render fullfrequency range audio content. In such a case, the full frequency rangeplayback device, when consolidated with the low frequency playbackdevice 200, may be configured to render only the mid and high frequencycomponents of audio content, while the low frequency range playbackdevice 200 renders the low frequency component of the audio content. Theconsolidated playback device may further be paired with a singleplayback device or yet another consolidated playback device.

By way of illustration, SONOS, Inc. presently offers (or has offered)for sale certain playback devices including a “PLAY:1,” “PLAY:3,”“PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any otherpast, present, and/or future playback devices may additionally oralternatively be used to implement the playback devices of exampleembodiments disclosed herein. Additionally, it is understood that aplayback device is not limited to the example illustrated in FIG. 2 orto the SONOS product offerings. For example, a playback device mayinclude a wired or wireless headphone. In another example, a playbackdevice may include or interact with a docking station for personalmobile media playback devices. In yet another example, a playback devicemay be integral to another device or component such as a television, alighting fixture, or some other device for indoor or outdoor use.

b. Example Playback Zone Configurations

Referring back to the media playback system 100 of FIG. 1, theenvironment may have one or more playback zones, each with one or moreplayback devices. The media playback system 100 may be established withone or more playback zones, after which one or more zones may be added,or removed to arrive at the example configuration shown in FIG. 1. Eachzone may be given a name according to a different room or space such asan office, bathroom, master bedroom, bedroom, kitchen, dining room,living room, and/or balcony. In one case, a single playback zone mayinclude multiple rooms or spaces. In another case, a single room orspace may include multiple playback zones.

As shown in FIG. 1, the balcony, dining room, kitchen, bathroom, office,and bedroom zones each have one playback device, while the living roomand master bedroom zones each have multiple playback devices. In theliving room zone, playback devices 104, 106, 108, and 110 may beconfigured to play audio content in synchrony as individual playbackdevices, as one or more bonded playback devices, as one or moreconsolidated playback devices, or any combination thereof. Similarly, inthe case of the master bedroom, playback devices 122 and 124 may beconfigured to play audio content in synchrony as individual playbackdevices, as a bonded playback device, or as a consolidated playbackdevice.

In one example, one or more playback zones in the environment of FIG. 1may each be playing different audio content. For instance, the user maybe grilling in the balcony zone and listening to hip hop music beingplayed by the playback device 102 while another user may be preparingfood in the kitchen zone and listening to classical music being playedby the playback device 114. In another example, a playback zone may playthe same audio content in synchrony with another playback zone. Forinstance, the user may be in the office zone where the playback device118 is playing the same rock music that is being playing by playbackdevice 102 in the balcony zone. In such a case, playback devices 102 and118 may be playing the rock music in synchrony such that the user mayseamlessly (or at least substantially seamlessly) enjoy the audiocontent that is being played out-loud while moving between differentplayback zones. Synchronization among playback zones may be achieved ina manner similar to that of synchronization among playback devices, asdescribed in previously referenced U.S. Pat. No. 8,234,395.

As suggested above, the zone configurations of the media playback system100 may be dynamically modified, and in some embodiments, the mediaplayback system 100 supports numerous configurations. For instance, if auser physically moves one or more playback devices to or from a zone,the media playback system 100 may be reconfigured to accommodate thechange(s). For instance, if the user physically moves the playbackdevice 102 from the balcony zone to the office zone, the office zone maynow include both the playback device 118 and the playback device 102.The playback device 102 may be paired or grouped with the office zoneand/or renamed if so desired via a control device such as the controldevices 126 and 128. On the other hand, if the one or more playbackdevices are moved to a particular area in the home environment that isnot already a playback zone, a new playback zone may be created for theparticular area.

Further, different playback zones of the media playback system 100 maybe dynamically combined into zone groups or split up into individualplayback zones. For instance, the dining room zone and the kitchen zone114 may be combined into a zone group for a dinner party such thatplayback devices 112 and 114 may render audio content in synchrony. Onthe other hand, the living room zone may be split into a television zoneincluding playback device 104, and a listening zone including playbackdevices 106, 108, and 110, if the user wishes to listen to music in theliving room space while another user wishes to watch television.

c. Example Control Devices

FIG. 3 shows a functional block diagram of an example control device 300that may be configured to be one or both of the control devices 126 and128 of the media playback system 100. As shown, the control device 300may include a processor 302, memory 304, a network interface 306, and auser interface 308. In one example, the control device 300 may be adedicated controller for the media playback system 100. In anotherexample, the control device 300 may be a network device on which mediaplayback system controller application software may be installed, suchas for example, an iPhone™, iPad™ or any other smart phone, tablet ornetwork device (e.g., a networked computer such as a PC or Mac™).

The processor 302 may be configured to perform functions relevant tofacilitating user access, control, and configuration of the mediaplayback system 100. The memory 304 may be configured to storeinstructions executable by the processor 302 to perform those functions.The memory 304 may also be configured to store the media playback systemcontroller application software and other data associated with the mediaplayback system 100 and the user.

In one example, the network interface 306 may be based on an industrystandard (e.g., infrared, radio, wired standards including IEEE 802.3,wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, 802.15, 4G mobile communication standard, and so on). Thenetwork interface 306 may provide a means for the control device 300 tocommunicate with other devices in the media playback system 100. In oneexample, data and information (e.g., such as a state variable) may becommunicated between control device 300 and other devices via thenetwork interface 306. For instance, playback zone and zone groupconfigurations in the media playback system 100 may be received by thecontrol device 300 from a playback device or another network device, ortransmitted by the control device 300 to another playback device ornetwork device via the network interface 306. In some cases, the othernetwork device may be another control device.

Playback device control commands such as volume control and audioplayback control may also be communicated from the control device 300 toa playback device via the network interface 306. As suggested above,changes to configurations of the media playback system 100 may also beperformed by a user using the control device 300. The configurationchanges may include adding/removing one or more playback devices to/froma zone, adding/removing one or more zones to/from a zone group, forminga bonded or consolidated player, separating one or more playback devicesfrom a bonded or consolidated player, among others. Accordingly, thecontrol device 300 may sometimes be referred to as a controller, whetherthe control device 300 is a dedicated controller or a network device onwhich media playback system controller application software isinstalled.

The user interface 308 of the control device 300 may be configured tofacilitate user access and control of the media playback system 100, byproviding a controller interface such as the controller interface 400shown in FIG. 4. The controller interface 400 includes a playbackcontrol region 410, a playback zone region 420, a playback status region430, a playback queue region 440, and an audio content sources region450. The user interface 400 as shown is just one example of a userinterface that may be provided on a network device such as the controldevice 300 of FIG. 3 (and/or the control devices 126 and 128 of FIG. 1)and accessed by users to control a media playback system such as themedia playback system 100. Other user interfaces of varying formats,styles, and interactive sequences may alternatively be implemented onone or more network devices to provide comparable control access to amedia playback system.

The playback control region 410 may include selectable (e.g., by way oftouch or by using a cursor) icons to cause playback devices in aselected playback zone or zone group to play or pause, fast forward,rewind, skip to next, skip to previous, enter/exit shuffle mode,enter/exit repeat mode, enter/exit cross fade mode. The playback controlregion 410 may also include selectable icons to modify equalizationsettings, and playback volume, among other possibilities.

The playback zone region 420 may include representations of playbackzones within the media playback system 100. In some embodiments, thegraphical representations of playback zones may be selectable to bringup additional selectable icons to manage or configure the playback zonesin the media playback system, such as a creation of bonded zones,creation of zone groups, separation of zone groups, and renaming of zonegroups, among other possibilities.

For example, as shown, a “group” icon may be provided within each of thegraphical representations of playback zones. The “group” icon providedwithin a graphical representation of a particular zone may be selectableto bring up options to select one or more other zones in the mediaplayback system to be grouped with the particular zone. Once grouped,playback devices in the zones that have been grouped with the particularzone will be configured to play audio content in synchrony with theplayback device(s) in the particular zone. Analogously, a “group” iconmay be provided within a graphical representation of a zone group. Inthis case, the “group” icon may be selectable to bring up options todeselect one or more zones in the zone group to be removed from the zonegroup. Other interactions and implementations for grouping andungrouping zones via a user interface such as the user interface 400 arealso possible. The representations of playback zones in the playbackzone region 420 may be dynamically updated as playback zone or zonegroup configurations are modified.

The playback status region 430 may include graphical representations ofaudio content that is presently being played, previously played, orscheduled to play next in the selected playback zone or zone group. Theselected playback zone or zone group may be visually distinguished onthe user interface, such as within the playback zone region 420 and/orthe playback status region 430. The graphical representations mayinclude track title, artist name, album name, album year, track length,and other relevant information that may be useful for the user to knowwhen controlling the media playback system via the user interface 400.

The playback queue region 440 may include graphical representations ofaudio content in a playback queue associated with the selected playbackzone or zone group. In some embodiments, each playback zone or zonegroup may be associated with a playback queue containing informationcorresponding to zero or more audio items for playback by the playbackzone or zone group. For instance, each audio item in the playback queuemay comprise a uniform resource identifier (URI), a uniform resourcelocator (URL) or some other identifier that may be used by a playbackdevice in the playback zone or zone group to find and/or retrieve theaudio item from a local audio content source or a networked audiocontent source, possibly for playback by the playback device.

In one example, a playlist may be added to a playback queue, in whichcase information corresponding to each audio item in the playlist may beadded to the playback queue. In another example, audio items in aplayback queue may be saved as a playlist. In a further example, aplayback queue may be empty, or populated but “not in use” when theplayback zone or zone group is playing continuously streaming audiocontent, such as Internet radio that may continue to play untilotherwise stopped, rather than discrete audio items that have playbackdurations. In an alternative embodiment, a playback queue can includeInternet radio and/or other streaming audio content items and be “inuse” when the playback zone or zone group is playing those items. Otherexamples are also possible.

When playback zones or zone groups are “grouped” or “ungrouped,”playback queues associated with the affected playback zones or zonegroups may be cleared or re-associated. For example, if a first playbackzone including a first playback queue is grouped with a second playbackzone including a second playback queue, the established zone group mayhave an associated playback queue that is initially empty, that containsaudio items from the first playback queue (such as if the secondplayback zone was added to the first playback zone), that contains audioitems from the second playback queue (such as if the first playback zonewas added to the second playback zone), or a combination of audio itemsfrom both the first and second playback queues. Subsequently, if theestablished zone group is ungrouped, the resulting first playback zonemay be re-associated with the previous first playback queue, or beassociated with a new playback queue that is empty or contains audioitems from the playback queue associated with the established zone groupbefore the established zone group was ungrouped. Similarly, theresulting second playback zone may be re-associated with the previoussecond playback queue, or be associated with a new playback queue thatis empty, or contains audio items from the playback queue associatedwith the established zone group before the established zone group wasungrouped. Other examples are also possible.

Referring back to the user interface 400 of FIG. 4, the graphicalrepresentations of audio content in the playback queue region 440 mayinclude track titles, artist names, track lengths, and other relevantinformation associated with the audio content in the playback queue. Inone example, graphical representations of audio content may beselectable to bring up additional selectable icons to manage and/ormanipulate the playback queue and/or audio content represented in theplayback queue. For instance, a represented audio content may be removedfrom the playback queue, moved to a different position within theplayback queue, or selected to be played immediately, or after anycurrently playing audio content, among other possibilities. A playbackqueue associated with a playback zone or zone group may be stored in amemory on one or more playback devices in the playback zone or zonegroup, on a playback device that is not in the playback zone or zonegroup, and/or some other designated device.

The audio content sources region 450 may include graphicalrepresentations of selectable audio content sources from which audiocontent may be retrieved and played by the selected playback zone orzone group. Discussions pertaining to audio content sources may be foundin the following section.

d. Example Audio Content Sources

As indicated previously, one or more playback devices in a zone or zonegroup may be configured to retrieve for playback audio content (e.g.according to a corresponding URI or URL for the audio content) from avariety of available audio content sources. In one example, audiocontent may be retrieved by a playback device directly from acorresponding audio content source (e.g., a line-in connection). Inanother example, audio content may be provided to a playback device overa network via one or more other playback devices or network devices.

Example audio content sources may include a memory of one or moreplayback devices in a media playback system such as the media playbacksystem 100 of FIG. 1, local music libraries on one or more networkdevices (such as a control device, a network-enabled personal computer,or a networked-attached storage (NAS), for example), streaming audioservices providing audio content via the Internet (e.g., the cloud), oraudio sources connected to the media playback system via a line-in inputconnection on a playback device or network devise, among otherpossibilities.

In some embodiments, audio content sources may be regularly added orremoved from a media playback system such as the media playback system100 of FIG. 1. In one example, an indexing of audio items may beperformed whenever one or more audio content sources are added, removedor updated. Indexing of audio items may involve scanning foridentifiable audio items in all folders/directory shared over a networkaccessible by playback devices in the media playback system, andgenerating or updating an audio content database containing metadata(e.g., title, artist, album, track length, among others) and otherassociated information, such as a URI or URL for each identifiable audioitem found. Other examples for managing and maintaining audio contentsources may also be possible.

The above discussions relating to playback devices, controller devices,playback zone configurations, and media content sources provide onlysome examples of operating environments within which functions andmethods described below may be implemented. Other operating environmentsand configurations of media playback systems, playback devices, andnetwork devices not explicitly described herein may also be applicableand suitable for implementation of the functions and methods.

e. Example Cloud Computing Functions

Various references are made herein to “cloud computing.” The term “cloudcomputing” is used to refer to services delivered using distributedcomputing over a network, such as the Internet. A non-exhaustive list ofservices delivered via the cloud include electronic mail (e.g., GMAIL®or HOTMAIL®), social networking (e.g., FACEBOOK®, LINKEDIN®, orTWITTER®), file hosting (e.g., DROPBOX®), and streaming audio (e.g.,SPOTIFY®, PANDORA®, or BEATSAUDIO®). Other cloud services are certainlyoffered as well.

Cloud service providers may offer one or more interfaces for accessingtheir service over a network. For instance, some cloud services may beaccessed by visiting a web site using a web browser. Other cloudservices are accessed by executing a particular application specific tothe cloud service on a computing device. Some cloud services may offeran application programming interface (API) to facilitate access to theservice by a third-party web site or application. In many cases, a userwho has access to a given cloud service can access the service from anycomputing device that is connected to the network, provided that thecomputing device has a supported interface to the cloud service.

In one instance, accessing a cloud service may involve accessing, with afirst computing device (i.e., a client), a second computing device(i.e., a server). Example client devices may include playback device 200of FIG. 2, or control device 300 of FIG. 3, among other possibledevices. One or more programs or applications (i.e., instructions) mayexecute on the server to perform computing tasks supported by the cloudservice. The client may send various commands to the server to instructthe server to perform the computing tasks supported by the cloudservice.

FIG. 5 illustrates an example computing system 500 that may provide acloud service to one or more users. Example computing system 500includes at least one processor 502, memory 504, and a network interface506. The memory 504 may contain instructions executable by the processor502 to perform computing tasks supported by a cloud service. Thecomputing device 500 may communicate with other computing devices viathe network interface 506.

In aggregate, the provision of a cloud service many involve multipleinstances of computing system 500. Each instance of computing system 500may provide the cloud service to one or more users. Cloud serviceproviders may scale the number of instances of computing system 500involved in providing the cloud service based on user demand.

FIG. 6 illustrates an example cloud 600. The example cloud 600 mayinclude any number of computing devices which are interconnected via oneor more networks. For instance, cloud 600 may include one or moreinstances of computing system 500. As shown in FIG. 6, media playbacksystems 610 and 620 are connected to cloud 600. In particular, mediaplayback system 610 includes playback devices 612 and 614 and controldevice 616, each having a respective connection to cloud 600. Likewise,media playback system 620 includes playback devices 622 and 624 andcontrol device 626, each having a respective connection to cloud 600.

Using the cloud 600, media playback systems 610 and 620 may accessvarious cloud services. For instance, media playback systems 610 and 620may also access one or more streaming audio services 602. As notedabove, streaming audio services may provide audio content to mediaplayback systems. Several example streaming audio services that arecurrently available include SPOTIFY®, PANDORA®, BEATSAUDIO®, RDIO®,GOOGLE PLAY MUSIC ALL ACCESS®, SONY MUSIC UNLIMITED®, ITUNES RADIO®,XBOX MUSIC®, and TUNEIN RADIO®. Other streaming audio services certainlyexist, and other streaming audio services may be offered in the future.

Media playback systems 610 and 620 may also access one or more socialnetwork services 604. Social network services are often characterized atleast in part by various links between users of the service. Such linksare referred to by different names, such as “friends”, “connections”,“followers”, or “favorites,” among other examples. Users may create suchlinks for various reasons. For instance, in some cases, the users mayhave a relationship outside of the social network (e.g., co-workers,relatives, or college friends). In other cases, two users may havesimilar interests (e.g., fans of a particular band or genre) or belongto a certain group and then form a link in the social network becausethey share these similar interests.

A cloud service provider may provide a cloud queue service 606. Thecloud queue service 606 may maintain or have access to one or moreplayback queues. In some cases, the cloud queue service 606 may maintaina playback queue for each media playback system registered with thecloud queue service 606. Such playback queues may be referred to ascloud queues. In other cases, the cloud queue service 606 may maintainmultiple cloud queues for each media playback system, perhaps with oneparticular playback queue “active” (i.e., “selected”) at any instant.

Various devices may access the playback queue to modify (e.g., add,remove, or re-order) media items in a playback queue maintained by cloudqueue service 606. Such devices may include control devices, such ascontrol device 300, or any suitable device having a network interface tocommunicate with the cloud queue service 606. Access to particularplayback queues may be limited to devices that are authenticated,authorized, or otherwise associated with a particular media playbacksystem. For instance, a media playback system may be associated with oneor more user accounts. Authenticating a device with the cloud queueservice 606 by way of one of these one or more user accounts may allowthe device to modify a playback queue maintained for the media playbacksystem.

A media playback system, such media playback systems 610 and 620, mayrequest media items from a cloud queue maintained for the media playbacksystem by a cloud queue service. For instance, media playback system 610may request media items from a particular cloud queue maintained formedia playback system 610 by cloud queue service 606. In someimplementations, the media playback system may maintain a copy (orsnapshot) of the cloud queue. The media playback system may play backmedia items from this copy.

From time to time, the media playback system may request media itemsfrom the cloud queue to update its copy of the cloud queue. Forinstance, media playback system 610 may request media items from theparticular cloud queue maintained for media playback system 610 toupdate its local instance of the cloud queue, perhaps stored on a memoryof a playback device, such as memory 206 of playback device 200.Further, in some examples, cloud queue service 606 may notify mediaplayback system 610 of changes to the particular cloud queue (e.g.,addition, removal, or re-ordering of media items in the particular cloudqueue). Based on such a notification, media playback system 610 mayrequest media items from the particular cloud queue maintained for mediaplayback system 610 to update its local instance of the cloud queue.

The above discussions relating to playback devices, controller devices,playback zone configurations, media content sources, and cloud computingprovide only some examples of operating environments within whichfunctions and methods described below may be implemented. Otheroperating environments and configurations of media playback systems,playback devices, and network devices not explicitly described hereinmay also be applicable and suitable for implementation of the functionsand methods.

III. Example Method/System to Remove Media Items from a Playback Queue

As discussed above, embodiments described herein may involve removingmedia items from a playback queue. Method 700 shown in FIG. 7 presentsan embodiment of a method that can be implemented within an operatingenvironment involving, for example, the media playback system 100 ofFIG. 1, one or more of the playback device 200 of FIG. 2, one or more ofthe control device 300 of FIG. 3, or one or more of the computing system500 of FIG. 5. Method 700 may include one or more operations, functions,or actions as illustrated by one or more of blocks 702-710. Although theblocks are illustrated in sequential order, these blocks may also beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

In addition, for the method 700 and other processes and methodsdisclosed herein, the flowchart shows functionality and operation of onepossible implementation of present embodiments. In this regard, eachblock may represent a module, a segment, or a portion of program code,which includes one or more instructions executable by a processor forimplementing specific logical functions or steps in the process. Theprogram code may be stored on any type of computer readable medium, forexample, such as a storage device including a disk or hard drive. Thecomputer readable medium may include non-transitory computer readablemedium, for example, such as computer-readable media that stores datafor short periods of time like register memory, processor cache andRandom Access Memory (RAM). The computer readable medium may alsoinclude non-transitory media, such as secondary or persistent long termstorage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. The computerreadable media may also be any other volatile or non-volatile storagesystems. The computer readable medium may be considered a computerreadable storage medium, for example, or a tangible storage device. Inaddition, for the method 500 and other processes and methods disclosedherein, each block in FIG. 8 may represent circuitry that is wired toperform the specific logical functions in the process.

a. Remove a Given Media Item from a Queue of Media Items.

At block 702, the method involves removing a given media item from aqueue of media items. For instance, a computing system, such ascomputing system 500 of FIG. 5, may remove a given media item from aqueue maintained by a cloud queue service, such as cloud queue service606.

FIG. 8A shows example playback queue 800A. Playback queue 800A is a listof entries 802-832. Entries 802-832 contain Songs A-P in positions 1-16,respectively. Songs A-P may represent any of the example audio itemsnoted above. Although playback queue 800A is shown with 15 entries,playback queue 800A may have additional or fewer entries if media itemsare added or removed from playback queue 800A. Playback queue 800A maybe maintained for a media playback system by a cloud queue service, suchas cloud queue service 606. For example, an instance of computing system500 of FIG. 5 (which may provide cloud queue service 606) may maintainplayback queue 800A for media playback system 610. In such an example,playback device 612 and/or playback device 616 may maintain a local copyof playback queue 800A, perhaps in a memory, such as memory 206 of FIG.2. Alternately, playback queue 800A may be maintained on anothercomputing system, such as an instance of control device 300 of FIG. 3.

As noted above, a local copy of a playback queue is not necessarily theplayback queue itself, or a copy of the queue per se. The local copy ofthe playback queue may represent information of the playback queue. Forinstance, the local copy of playback queue 800A may include data thatrepresent entries 802-832 (containing Songs A-P in positions 1-16), suchthat, based on the local copy, the media playback system may detect themedia items queued in playback queue 800A and the ordering thereof.

In one example, the computing system may remove song C in position 3from entry 806 in queue 800A. FIG. 8B shows example playback queue 800B,which represents playback queue 800A after the computing system removedsong C in position 3 from entry 806.

In some examples, the computing system may receive, via a networkinterface, a command to remove the given media item from the queue ofmedia items. Such a command may be sent from a device that iscommunicatively coupled to the computing system via a network. In somecases, the device may detect input at a user interface that indicates aselection of one or more media items for removal from the queue. Forinstance, control device 616 of FIG. 6 may detect input selecting song Cin position 3 for removal from the queue. Based on the received commandto remove the given media item (e.g., in response to the receivedcommand), the computing system may remove the given media item from thequeue of media items.

As noted above, the computing system may receive a command to remove thegiven media item from the queue of media items. In some implementations,based on such a received command, the computing system may send, via thenetwork interface, at least one message that indicates that the queue ofmedia items has been altered. For instance, the computing system maysend a message to playback device 612, which may be a zone “coordinator”that stores a local copy of the playback queue on behalf of the zonethat other playback devices in the zone (e.g., playback device 614) mayaccess. Alternatively, the computing system may send the message tomultiple playback devices within a group (e.g., playback device 612 and614). Such a message may notify that playback devices that theirrespective local copies of playback queue 800A are out-of-date (asremoval of song C has altered playback queue 800A). In some cases, thecomputing system may broadcast the message to all playback devices in amedia playback system. In other cases, the computing system may send themessage to one or more playback devices, which may then send anindication that the queue of media items has been altered to otherplayback devices of the media playback system.

b. Add to the Queue an Indication that the Given Media Item has BeenRemoved from the Queue.

At block 704, the method involves adding to the queue an indication thatthe given media item has been removed from the queue. For instance, thecomputing system may add an indication to queue 800B that Song C hasbeen removed from queue 800B. Such an indication may be referred to as a“tombstone.”

Adding an indication that the given media item has been removed from thequeue may be implemented in a variety of ways. In some cases, a table,array, or other data structure that represents the queue may containentries or other containers that represent the media items in the queue.In such an example, adding to the queue an indication that the givenmedia item has been removed from the queue may involve adding to thequeue an entry that indicates that the given media item has been removedfrom the queue. FIG. 8C shows example playback queue 800C, whichrepresents playback queue 800B after adding, to queue 800B, theindication that Song C has been removed from queue 800B. As shown, queue800C includes an entry 806 that indicates that Song C has been removedfrom the queue. The entry may indicate a position of the given mediaitem in the queue of media items before the given media item was removed(i.e., position 3 for Song C).

In another example, adding to the queue the indication may involveassociating data (indicating that the given media item has been removedfrom the queue) with the queue. For instance, the playback queue mayinclude metadata that may indicate media items that have been removedfrom the queue. Alternatively, the playback queue may contain areference to (or be otherwise associated with) data that may indicatemedia items that have been removed from the queue.

In some examples, each media item in the queue of media items isassigned a unique identifier. The unique identifier may be a uniformresource identifier (URI), a uniform resource locator (URL) or someother identifier that may be used by a playback device in the playbackzone or zone group to find and/or retrieve the audio item from a localaudio content source or a networked audio content source, possibly forplayback by the playback device. The removed item may have previouslybeen assigned a given unique identifier (e.g., a URI indicating theremoved item). In such cases, adding to the queue an indication that thegiven media item has been removed from the queue may involve adding anentry to the queue that indicates the given identifier such that theentry indicates the removed media item via the given identifier. Forexample, Song C may be assigned a particular URI, and entry 806 thatindicates that Song C has been removed from the queue may indicate SongC by the particular URI assigned to Song C.

c. Receive One or More Requests for One or More Media Items from theQueue of Media Items.

At block 706, the method involves receiving one or more requests for oneor more media items from the queue of media items. For instance, afteradding to the queue the indication, the computing system may receive oneor more requests for one or more media items from playback queue 800C.In some examples, the requests may be sent from one or more playbackdevices, such as playback device 612 and/or 614. As noted above,playback devices may send requests for one or more media items to thecloud queue service to update their respective copies of playback queue800C. Alternatively, a control device, such as control device 616, maysend one or more of the requests.

As noted above, a device of a media playback system may make such arequest to synchronize a local copy of the playback queue (or a portionthereof) with the playback queue. Accordingly, each request for one ormore media items may be a request for one or more media items in a listfrom the playback queue. The one or more media items requested mayinclude a media item that is currently playing at the media playbacksystem (and perhaps one or more media items queued after the currentlyplaying media item such that the media items that are queued next in theplayback queue can be synced to the local queue for playback at themedia playback system). For instance, a particular media item (e.g.,Song A) may be playing on media playback system 610 from a local copy ofqueue 800A. Playback device 612 (or playback device 614) may request alist of media items from queue 800A starting at (or including) Song A.This list of media items may be referred to as a “window” and the numberof media items requested may be referred to a “window size.” An examplewindow size may be 10 media items (provided that there are at least 10media items in the playback queue), among other example sizes.

The window need not necessarily include the currently playing mediaitem. For example, in some cases, playback at the media playback systemmay be stopped. In such a case, the window may include one or more mediaitems that are ordered first in the playback queue such that they wouldbe the first media items to playback if playback was initiated at themedia playback system. Alternatively, the window may include one or moremedia items succeeding the currently playing media item in the playbackqueue.

As noted above, Song C may be removed from queue 800A, which may causethe computing system to send a notification to media playback system 610indicating that queue 800A has been altered. Such a notification maycause playback device 612 to request a list of media items from queue800C starting at (or including) Song C (which may be, for example,currently playing on media playback system 610). Playback device 612 maythen request a list of media items from queue 800C starting at (orincluding) Song C. The computing system may then send the requested listof media items from queue 800C that starts at (or includes) Song C tomedia playback system 610.

To determine which songs to include in the window, the computing systemmay search for Song C (the currently playing media item). After findingSong C, the computing system may include Song C and one or moreadditional media items in the window. If the indication is not includedin the list of media items, the computing system might not know whichmedia items to send to playback device 612, as Song C has been removedand the computing system might be unable to find Song C when searching.To avoid this problem, the list of media items sent to media playbacksystem 610 may include the indication in position 3 that Song C has beenremoved from queue 800A. After receiving the list of media items sent bythe computing system, a device (e.g., playback device 612) may detectthe indication in position 3 that Song C has been removed from queue800A, and responsively remove Song C from its local copy of the playbackqueue.

d. Determine that More than a Threshold Number of Requests for One orMore Media Items Have Been Received Since Adding to the Queue theIndication.

At block 708, the method involves determining that the computing systemhas received more than a threshold number of requests for one or moremedia items since adding to the queue the indication. For instance, thecomputing system may determine that the computing system has receivedthan a threshold number of requests since adding the indication thatSong C has been removed from playback queue 800C. Alternatively, themethod may involve determining that the computing system has receivedthe threshold number of requests for one or more media items sinceadding to the queue the indication.

The threshold number of requests may be at least one. However, athreshold that is configured at a number of requests that is greaterthan one may address some corner cases that may arise with a thresholdthat is configured at one request. For instance, as an alteration of theexample above, Song C and Song D may be removed from the playback queueand replaced by indications that the respective audio items have beenremoved from the queue. FIG. 8D shows an example queue 800D, whichrepresents playback queue 800B after adding the indications that Song Cand Song D have been removed from queue 800B.

Removal of Song C and Song D may cause the computing system to notifymedia playback system 610 that queue 800A has been altered. At thistime, song C may be now playing on media playback system 610. Playbackdevice 612 may then request a list of media items from queue 800Cstarting at (or including) Song C. As noted above, the list of mediaitems may include the indications in positions 3 and 4 that Songs C andD have been removed from the queue. Playback device 612 may detect suchindications, and responsively remove Song C and Song D from its localcopy of the playback queue. Given a threshold of one, the computingsystem may determine that the threshold has been reached, and remove theindications from the queue.

However, in some cases, playback of Track 3 may end before it receivesthe list of media items. The playback device may then request a new listof media items from queue 800D starting at (or including) Song D. If asnoted above, the computing system removed the indication of Song D fromthe queue, the computing system might not know which media items to sendto playback device 612, as Song D has been removed. To avoid situationslike this, the threshold may be configured at two requests or threerequests. The threshold may be configured at a higher number ofrequests, however, such an embodiment may use additional computingand/or network resources.

In some cases, the computing system may maintain or have access to acounter for indication (or entry) that indicates a removed media item.Based on each received request for one or media items from the queue ofmedia items, the computing system may increment the counter associatedwith each indication. Then, the value of each counter may indicate anumber of requests for one or media items from the queue of media itemsthat have been received since adding the indication to the queue. Suchcounters may facilitate determining that the computing system hasreceived a threshold number of requests. For instance, based on theincremented counter associated with the indication, the computing systemmay determine that the computing system has received a threshold numberof requests for one or media items from the queue of media items sinceadding to the queue the entry.

e. Remove the Indication from the Queue.

At block 710, the method involves removing the indication from thequeue. For instance, after determining that the computing system hasreceived more than the threshold number of requests, the computingsystem may remove the indications for Song C and Song D from queue 800D.Such an operation may involve removing indications from a data structure(e.g., an array or a table) that represents queue 800D. Alternatively,such an operation may involve removing a reference in queue 800D to datathat indicates that Songs C and D were removed from the queue. Inanother example, removing the indication may involve deleting metadata(that indicates Songs C and D were removed from the queue) which couldbe contained in the data structure that represents the playback queue(or otherwise associated with the playback queue), perhaps in a seconddata structure that is referenced by the data structure that representsthe playback queue.

FIG. 8E shows an example queue 800E, which represents playback queue800D after removing the indications that Song C and Song D have beenremoved from the queue. As shown in FIG. 8E, the computing system mayupdate entries 802-828 with new position numbering to reflect thecurrent order of the Songs in the entries.

IV. Conclusion

The description above discloses, among other things, various examplesystems, methods, apparatus, and articles of manufacture including,among other components, firmware and/or software executed on hardware.It is understood that such examples are merely illustrative and shouldnot be considered as limiting. For example, it is contemplated that anyor all of the firmware, hardware, and/or software aspects or componentscan be embodied exclusively in hardware, exclusively in software,exclusively in firmware, or in any combination of hardware, software,and/or firmware. Accordingly, the examples provided are not the onlyway(s) to implement such systems, methods, apparatus, and/or articles ofmanufacture.

As indicated above, the present application involves removing a mediaitem from a playback queue. In one aspect, a method is provided. Themethod may involve removing a given media item from a queue of mediaitems. The method may further involve adding to the queue an indicationthat the given media item has been removed from the queue. Afterreceiving the one or more requests, the method may also involvedetermining that the computing system has received more than a thresholdnumber of requests for one or more media items since adding to the queuethe indication. After determining that the computing system has receivedmore than the threshold number of requests, the method may furtherinvolve removing the indication from the queue.

In another aspect, a device is provided. The device includes a networkinterface, at least one processor, a data storage, and program logicstored in the data storage and executable by the at least one processorto perform functions. The functions may include removing a given mediaitem from a queue of media items. The functions may further includeadding to the queue an indication that the given media item has beenremoved from the queue. After receiving the one or more requests, thefunctions may also include determining that the computing system hasreceived more than a threshold number of requests for one or more mediaitems since adding to the queue the indication. After determining thatthe computing system has received more than the threshold number ofrequests, the functions may further include removing the indication fromthe queue.

In yet another aspect, a non-transitory computer readable memory isprovided. The non-transitory computer readable memory has stored thereoninstructions executable by a computing device to cause the computingdevice to perform functions. The functions may include removing a givenmedia item from a queue of media items. The functions may furtherinclude adding to the queue an indication that the given media item hasbeen removed from the queue. After receiving the one or more requests,the functions may also include determining that the computing system hasreceived more than a threshold number of requests for one or more mediaitems since adding to the queue the indication. After determining thatthe computing system has received more than the threshold number ofrequests, the functions may further include removing the indication fromthe queue.

Additionally, references herein to “embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment can be included in at least one example embodiment of aninvention. The appearances of this phrase in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. As such, the embodiments described herein, explicitly andimplicitly understood by one skilled in the art, can be combined withother embodiments.

The specification is presented largely in terms of illustrativeenvironments, systems, procedures, steps, logic blocks, processing, andother symbolic representations that directly or indirectly resemble theoperations of data processing devices coupled to networks. These processdescriptions and representations are typically used by those skilled inthe art to most effectively convey the substance of their work to othersskilled in the art. Numerous specific details are set forth to provide athorough understanding of the present disclosure. However, it isunderstood to those skilled in the art that certain embodiments of thepresent disclosure can be practiced without certain, specific details.In other instances, well known methods, procedures, components, andcircuitry have not been described in detail to avoid unnecessarilyobscuring aspects of the embodiments. Accordingly, the scope of thepresent disclosure is defined by the appended claims rather than theforgoing description of embodiments.

When any of the appended claims are read to cover a purely softwareand/or firmware implementation, at least one of the elements in at leastone example is hereby expressly defined to include a tangible,non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on,storing the software and/or firmware.

I claim:
 1. A method to be performed by a computing system, the methodcomprising: receiving, via a network interface, instructions to remove aparticular media item from a playback queue, wherein one or moreplayback devices of a media playback system are configured to play backmedia items according to the playback queue; based on receiving theinstructions to remove the particular media item from the playbackqueue, removing the particular media item from the playback queue;adding, to the playback queue, a tombstone indicator indicating that theparticular media item has been removed from the playback queue;receiving, via the network interface from the media playback system, arequest for a window of one or more media items from the playback queue;based on receiving the request for the window, sending, via the networkinterface to the media playback system, data representing a particularwindow of media items from the playback queue, wherein the particularwindow includes the tombstone indicator; detecting a given tombstoneremoval trigger from among multiple tombstone removal triggers; andbased on detecting the given tombstone removal trigger, removing thetombstone indicator from the playback queue.
 2. The method of claim 1,further comprising: receiving, via the network interface from the mediaplayback system, multiple requests for a window of media items from theplayback queue, wherein detecting the given tombstone removal triggercomprises determining that a count of the multiple requests received bythe computing system is at least a threshold number of requests sincethe tombstone indicator was added to the playback queue.
 3. The methodof claim 1, further comprising: receiving, via the network interfacefrom the media playback system, multiple queue interactions, whereindetecting the given tombstone removal trigger comprises determining thata count of the multiple queue interactions received by the computingsystem is at least a threshold number of queue interactions since thetombstone indicator was added to the playback queue, and wherein a queueinteraction comprises one of (a) modifying the playback queue or (b)requesting a window of media items from the playback queue.
 4. Themethod of claim 1, wherein detecting the given tombstone removal triggercomprises detecting that a threshold period of time has elapsed sincethe tombstone indicator was added to the playback queue.
 5. The methodof claim 1, further comprising: based on adding the tombstone indicatorindicating that the particular media item has been removed from theplayback queue, sending, via the network interface to the media playbacksystem, instructions to send a request for a window of media items,wherein the media playback system sends the request for the window ofone or more media items from the playback queue based on receiving theinstructions to send the request for a window of media items.
 6. Themethod of claim 1, wherein the particular window further includes (i) afirst media item that is currently playing back on the one or moreplayback devices, (ii) one or more second media items that precede thegiven media item in the playback queue and (iii) one or more third mediaitems subsequent to the given media item in the playback queue.
 7. Themethod of claim 1, wherein sending the data representing the particularwindow of media items from the playback queue comprises sending datarepresenting respective sources of the media items in the window at oneor more remote servers.
 8. A system comprising one or more servers, thesystem configured to perform functions comprising: receiving, via anetwork interface, instructions to remove a particular media item from aplayback queue, wherein one or more playback devices of a media playbacksystem are configured to play back media items according to the playbackqueue; based on receiving the instructions to remove the particularmedia item from the playback queue, removing the particular media itemfrom the playback queue; adding, to the playback queue, a tombstoneindicator indicating that the particular media item has been removedfrom the playback queue; receiving, via the network interface from themedia playback system, a request for a window of one or more media itemsfrom the playback queue; based on receiving the request for the window,sending, via the network interface to the media playback system, datarepresenting a particular window of media items from the playback queue,wherein the particular window includes the tombstone indicator;detecting a given tombstone removal trigger from among multipletombstone removal triggers; and based on detecting the given tombstoneremoval trigger, removing the tombstone indicator from the playbackqueue.
 9. The system of claim 8, wherein the system is furtherconfigured to perform functions comprising: receiving, via the networkinterface from the media playback system, multiple requests for a windowof media items from the playback queue, wherein detecting the giventombstone removal trigger comprises determining that a count of themultiple requests received by the one or more servers is at least athreshold number of requests since the tombstone indicator was added tothe playback queue.
 10. The system of claim 8, wherein the system isfurther configured to perform functions comprising: receiving, via thenetwork interface from the media playback system, multiple queueinteractions, wherein detecting the given tombstone removal triggercomprises determining that a count of the multiple queue interactionsreceived by the one or more servers is at least a threshold number ofqueue interactions since the tombstone indicator was added to theplayback queue, and wherein a queue interaction comprises one of (a)modifying the playback queue or (b) requesting a window of media itemsfrom the playback queue.
 11. The system of claim 8, wherein detectingthe given tombstone removal trigger comprises detecting that a thresholdperiod of time has elapsed since the tombstone indicator was added tothe playback queue.
 12. The system of claim 8, wherein the system isfurther configured to perform functions comprising: based on adding thetombstone indicator indicating that the particular media item has beenremoved from the playback queue, sending, via the network interface tothe media playback system, instructions to send a request for a windowof media items, wherein the media playback system sends the request forthe window of one or more media items from the playback queue based onreceiving the instructions to send the request for a window of mediaitems.
 13. The system of claim 8, wherein the particular window furtherincludes (i) a first media item that is currently playing back on theone or more playback devices, (ii) one or more second media items thatprecede the given media item in the playback queue and (iii) one or morethird media items subsequent to the given media item in the playbackqueue.
 14. The system of claim 8, wherein sending the data representingthe particular window of media items from the playback queue comprisessending data representing respective sources of the media items in thewindow at one or more remote servers.
 15. A tangible, non-transitory,computer-readable medium storing instructions that, when executed by oneor more processors, cause a computing system to perform functionscomprising: receiving, via a network interface, instructions to remove aparticular media item from a playback queue, wherein one or moreplayback devices of a media playback system are configured to play backmedia items according to the playback queue; based on receiving theinstructions to remove the particular media item from the playbackqueue, removing the particular media item from the playback queue;adding, to the playback queue, a tombstone indicator indicating that theparticular media item has been removed from the playback queue;receiving, via the network interface from the media playback system, arequest for a window of one or more media items from the playback queue;based on receiving the request for the window, sending, via the networkinterface to the media playback system, data representing a particularwindow of media items from the playback queue, wherein the particularwindow includes the tombstone indicator; detecting a given tombstoneremoval trigger from among multiple tombstone removal triggers; andbased on detecting the given tombstone removal trigger, removing thetombstone indicator from the playback queue.
 16. The tangible,non-transitory, computer-readable medium of claim 15, wherein thefunctions further comprise: receiving, via the network interface fromthe media playback system, multiple requests for a window of media itemsfrom the playback queue, wherein detecting the given tombstone removaltrigger comprises determining that a count of the multiple requestsreceived by the computing system is at least a threshold number ofrequests since the tombstone indicator was added to the playback queue.17. The tangible, non-transitory, computer-readable medium of claim 15,wherein the functions further comprise: receiving, via the networkinterface from the media playback system, multiple queue interactions,wherein detecting the given tombstone removal trigger comprisesdetermining that a count of the multiple queue interactions received bythe computing system is at least a threshold number of queueinteractions since the tombstone indicator was added to the playbackqueue, and wherein a queue interaction comprises one of (a) modifyingthe playback queue or (b) requesting a window of media items from theplayback queue.
 18. The tangible, non-transitory, computer-readablemedium of claim 15, wherein detecting the given tombstone removaltrigger comprises detecting that a threshold period of time has elapsedsince the tombstone indicator was added to the playback queue.
 19. Thetangible, non-transitory, computer-readable medium of claim 15, whereinthe functions further comprise: based on adding the tombstone indicatorindicating that the particular media item has been removed from theplayback queue, sending, via the network interface to the media playbacksystem, instructions to send a request for a window of media items,wherein the media playback system sends the request for the window ofone or more media items from the playback queue based on receiving theinstructions to send the request for a window of media items.
 20. Thetangible, non-transitory, computer-readable medium of claim 15, whereinthe particular window further includes (i) a first media item that iscurrently playing back on the one or more playback devices, (ii) one ormore second media items that precede the given media item in theplayback queue and (iii) one or more third media items subsequent to thegiven media item in the playback queue.